fix: enforce strict config validation

src/cli/program.smoke.test.ts

@@ -43,6 +43,11 @@ vi.mock("../tui/tui.js", () => ({ runTui }));
 vi.mock("../gateway/call.js", () => ({
   callGateway,
   randomIdempotencyKey: () => "idem-test",
+  buildGatewayConnectionDetails: () => ({
+    url: "ws://127.0.0.1:1234",
+    urlSource: "test",
+    message: "Gateway target: ws://127.0.0.1:1234",
+  }),
 }));
 vi.mock("./deps.js", () => ({ createDefaultDeps: () => ({}) }));